DOWNTOWN SAN DIEGO  Half of the homeless people in downtown San Diego are women and most are on the street because they lost their job or their housing, according to a recent survey from a group behind a $31 million plan to turn the city-owned, former World Trade Center into a homeless facility.

In a survey last month, Los Angeles-based People Assisting The Homeless (PATH) counted about 300 people living on the street in the downtown core. Fifteen percent of them were questioned.

The average time a homeless person surveyed had been on the street was four years, and the average time they had been in San Diego was 19 years. About two-thirds of the group interviewed have a serious medical condition, 40 percent said they abuse alcohol and 16 percent have prison records.

One third have family in the area and a quarter have incomes of up to $1,000 monthly, mainly from federal assistance programs.

“We think this group is housing ready,” said Joel John Roberts, chief executive director of PATH. “Not just shelter ready but permanent housing ready,” he said.

PATH and its San Diego partners, Affirmed Housing Group and Family Health Centers, want to convert the high-rise on Sixth Avenue into a one-stop homeless center with 150 interim housing units, 73 permanent ones, a health clinic and offices offering various social services.

A task force led by the San Diego Housing Commission in April recommended a plan to replace the city’s annual winter shelter program. The City Council could hear the proposal this summer.

Proponents, at the request of a council committee, are meeting with downtown groups and others to explain their proposal and seek input.

Business owners have raised the most concern, saying it would devastate the area’s increasingly upscale environment. “I support the one-stop idea, but the problem I and many people have is the location of the World Trade Center right in the middle of the B Street financial corridor,” said Tim Cowden, a commercial real estate consultant.

Cowden also pointed out that the proposed homeless shelter would be near a day care center. He has suggested officials consider the city’s Main Library on E Street instead, because a plan to build a new library near Petco Park is moving forward. Another group is proposing the city buy and convert the U.S. Postal Service’s former main distribution center on Midway Drive into a homeless facility.

Roberts and other supporters of the plan said there would be tight security at the center and that the facility’s spacious reception area would prevent lines from forming outside the building. The facility would exclude registered sex offenders and anyone with a record of a violent crime or serious drug offenses from living there.

Supporters say the building’s availability, size, price and proximity to a large homeless population make it the best location. Funding would likely include money from the city’s Redevelopment Agency, Housing Commission and federal tax credits.